全文获取类型
收费全文 | 69篇 |
免费 | 2篇 |
专业分类
化学 | 38篇 |
数学 | 1篇 |
物理学 | 32篇 |
出版年
2022年 | 1篇 |
2020年 | 2篇 |
2018年 | 1篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2012年 | 7篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1902年 | 1篇 |
1896年 | 1篇 |
排序方式: 共有71条查询结果,搜索用时 15 毫秒
1.
2.
Bowmaker GA Harris RK Assadollahzadeh B Apperley DC Hodgkinson P Amornsakchai P 《Magnetic resonance in chemistry : MRC》2004,42(9):819-826
Solid-state cross-polarization magic-angle spinning (CP/MAS) NMR spectra were recorded for the compounds [Ag(NH3)2]2SO4, [Ag(NH3)2]2SeO4 and [Ag(NH3))]NO3, all of which contain the linear or nearly linear two-coordinate [Ag(NH3)2]+ ion. The 109Ag CP/MAS NMR spectra show centrebands and associated spinning sideband manifolds typical for systems with moderately large shielding anisotropy, and splittings due to indirect 1J(109Ag,14N) spin-spin coupling. Spinning sideband analysis was used to determine the 109Ag shielding anisotropy and asymmetry parameters Deltasigma and eta from these spectra, yielding anisotropies in the range 1500-1600 ppm and asymmetry parameters in the range 0-0.3. Spectra were also recorded for 15N and (for the selenate) 77Se. In all cases the number of resonances observed is as expected for the crystallographic asymmetric units. The crystal structure of the selenate is reported for the first time. One-bond (107, 109Ag,15N) coupling constants are found to have magnitudes in the range 60-65 Hz. Density functional calculations of the Ag shielding tensor for model systems yield results that are in good agreement with the experimentally determined shielding parameters, and suggest that in the solid compounds Deltasigma and eta are reduced and increased, respectively, from the values calculated for the free [Ag(NH3)2]+ ion (1920 ppm and 0, respectively), primarily as a result of cation-cation interactions, for which there is evidence from the presence of metal-over-metal stacks of [Ag(NH3)2]+ ions in the solid-state structures of these compounds. 相似文献
3.
4.
Daniel T. W. Toolan Richard Hodgkinson Jonathan R. Howse 《Journal of Polymer Science.Polymer Physics》2014,52(1):17-25
Spin‐coated polymer blends possess a rich variety of accessible non‐equilibrium morphologies, formed through a process of phase separation and self‐assembly, the complexities of which remain incompletely understood. The technique of stroboscopic microscopy has now been developed to allow direct observations of microscopic and mesoscopic morphological development during spin‐coating and has afforded unequivocal information regarding morphological development. The technique so far has three modes of operation providing information on topographical, compositional, and crystal development. In this review, we look at the technique's development, its applications and comment on the future potential for this technique. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 17–25 相似文献
5.
Effects of Quantum Nuclear Delocalisation on NMR Parameters from Path Integral Molecular Dynamics 下载免费PDF全文
Dr. Martin Dračínský Dr. Paul Hodgkinson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2201-2207
The influence of nuclear delocalisation on NMR chemical shifts in molecular organic solids is explored using path integral molecular dynamics (PIMD) and density functional theory calculations of shielding tensors. Nuclear quantum effects are shown to explain previously observed systematic deviations in correlations between calculated and experimental chemical shifts, with particularly large PIMD‐induced changes (up to 23 ppm) observed for carbon atoms in methyl groups. The PIMD approach also enables isotope substitution effects on chemical shifts and J couplings to be predicted in excellent agreement with experiment for both isolated molecules and molecular crystals. An approach based on convoluting calculated shielding or coupling surfaces with probability distributions of selected bond distances and valence angles obtained from PIMD simulations is used to calculate isotope effects. 相似文献
6.
7.
Ohne Zusammenfassung 相似文献
8.
Combating Multidrug‐Resistant Bacteria: Current Strategies for the Discovery of Novel Antibacterials
Dr. Kieron M. G. O'Connell Dr. James T. Hodgkinson Dr. Hannah F. Sore Dr. Martin Welch Prof. George P. C. Salmond Dr. David R. Spring 《Angewandte Chemie (International ed. in English)》2013,52(41):10706-10733
The introduction of effective antibacterial therapies for infectious diseases in the mid‐20th century completely revolutionized clinical practices and helped to facilitate the development of modern medicine. Many potentially life‐threatening conditions became easily curable, greatly reducing the incidence of death or disability resulting from bacterial infections. This overwhelming historical success makes it very difficult to imagine life without effective antibacterials; however, the inexorable rise of antibiotic resistance has made this a very real and disturbing possibility for some infections. The ruthless selection for resistant bacteria, coupled with insufficient investment in antibacterial research, has led to a steady decline in the efficacy of existing therapies and a paucity of novel structural classes with which to replace them, or complement their use. This situation has resulted in a very pressing need for the discovery of novel antibiotics and treatment strategies, the development of which is likely to be a key challenge to 21st century medicinal chemistry. 相似文献
9.
Kenwright JL Galloway WR Blackwell DT Isidro-Llobet A Hodgkinson J Wortmann L Bowden SD Welch M Spring DR 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(10):2981-2986
Herein, a new copper-catalysed strategy for the synthesis of rare nitrogen-linked seven-, eight- and nine-membered biaryl ring systems is described. It is proposed that the reaction proceeds through a highly activated intramolecularly co-ordinated copper catalyst. The process is technically simple, proceeds under relatively mild conditions, displays a broad substrate scope and forms biologically valuable products that are difficult to synthesise by other methods. We envisage that this methodology will prove useful in a wide synthetic context, with possible applications in both target-oriented and diversity-oriented synthesis. 相似文献
10.
Ambichiral layered structures can be designed to function reasonably well as rejection filters for elliptical polarization states, although the proposed design strategy is inadequate for linear and quasilinear polarization states. 相似文献